What is the most effective way to learn a new song?

I’m a beginner. My long term goal is to be able to comp and improvise with a jazz band (for fun).

How can I learn new songs efficiently?

  • Focus on mastering each section before moving on?
  • Know how to play the song first with just root note + shells?
  • When should I move on to other tunes?

Is there any material on this? I’d love to know your protocol.